Planning for Cisco Emergency Responder

Cisco Emergency Responder (Cisco ER) helps you manage emergency calls in your telephony network so that you can respond to these calls effectively and so that you can comply with local ordinances concerning the handling of emergency calls. In North America, these local ordinances are called "enhanced 911," or E911. Other countries and locales might have similar ordinances.

Because emergency call ordinances can differ from location to location within a country, region, state, or even metropolitan area, Cisco ER includes the flexibility you need to fit your emergency call configuration to specific local requirements. However, because ordinances do differ from location to location, and because security requirements differ from company to company, you need to do extensive planning and research before you can deploy Cisco ER in a manner that fits your legal and security needs.

These topics help you understand emergency call ordinances, how Cisco ER helps you meet the ordinances, and what you need to do to deploy Cisco ER successfully:

Understanding Enhanced 911 (E911)

Enhanced 911, or E911, is an extension of the basic 911 emergency call standard in North America. These topics describe E911 requirements and terminology.

Overview of Enhanced 911 Requirements

Enhanced 911 (E911) extends the basic 911 emergency call standard to make it more reliable.

In basic 911 in North America, if a caller dials 911, the call is routed to a public safety answering point (PSAP), also called the 911 operator. The PSAP is responsible for talking to the caller and arranging the appropriate emergency response, such as sending police, fire, or ambulance teams.

E911 extends this standard with these requirements:

The emergency call must be routed to the local PSAP based on the location of the caller. In basic 911, the call simply needs to be routed to some PSAP, not necessarily the local one.
The caller's location information must be displayed at the emergency operator's terminal. This information is obtained by querying an automatic location information (ALI) database.

In E911, the location of the caller is determined by the emergency location identification number (ELIN), which is a phone number the PSAP can dial to reconnect to the emergency caller if the emergency call is cut off for any reason, or if the PSAP simply needs to talk to the caller again. The emergency call is routed to the PSAP based on the location information associated with this number. For multi-line phone systems, such as an office system, the ELIN can be associated with more than one telephone by grouping the phones in an emergency response location (ERL). In this case, the location the PSAP receives would be the address of an office building. For large buildings, the location would include additional information such as floor or region on a floor. Each ERL requires a unique ELIN.

In addition to these general E911 requirements, each locality can further extend or limit these requirements. For example, a city ordinance might include specific limitations on the size of an ERL (such as, no larger than 7,000 square feet), or on the number of phones that can be included in an ERL (such as, no more than 48 phones). You must work with your service provider and local government to determine the exact E911 requirements in your area.

Understanding E911 and Cisco Emergency Responder Terminology

Table 1-1 defines some of the key terminology used in this document.

Table 1-1 E911 and Cisco Emergency Responder Terminology

Term	Definition
ALI	Automatic location information. Information that ties an ELIN to a location, and is used to route emergency calls from that ELIN to the correct local PSAP. Information that is presented to the PSAP to help the PSAP locate the emergency caller. In Cisco Emergency Responder (Cisco ER), you fill in ALI data for each ERL, and submit the ALI data to your service provider for inclusion in the ALI database.
ANI	Automatic number identification. ANI is another name for ELIN. This document uses ELIN instead of ANI.
CAMA	Centralized automated message accounting. An analog phone trunk that connects directly to an E911 selective router, bypassing the PSTN.
DID	Direct inward dial. A telephone number obtained from your service provider that can be used to dial into your telephone network. DIDs are used for ELINs.
ELIN	Emergency location identification number. A phone number that routes the emergency call to the local PSAP, and which the PSAP can use to call back the emergency caller. The PSAP might need to call the number if the emergency call is cut off, or if the PSAP needs additional information after normally ending the emergency call. See ALI.
emergency call	A call made to the local emergency number, such as 911. Cisco ER routes the call to the service provider's network, where the call is routed to the local public safety answering point (PSAP).
emergency caller	The person who places the emergency call. The caller might require help for a personal emergency, or might be reporting a more general emergency (fire, theft, accident, and so forth).
ERL	Emergency response location. The area from which an emergency call is placed. This is not necessarily the location of the emergency. If an emergency caller is reporting a general emergency, the actual emergency might be in a different area. In Cisco ER, you assign switch ports and phones to ERLs, and ERL definitions include ALI data.
ESZ	Emergency service zone. The area covered by a given PSAP. This area usually includes several police and fire departments. For example, a city and its suburbs might be serviced by one PSAP. Each ESZ is assigned a unique emergency service number (ESN) to identify it.
MSAG	Master street address guide. A database of ALIs that enables proper routing of emergency calls to the correct PSAP. In Cisco ER, you export your ALI definitions and transmit them to your service provider, who ensures the MSAG is updated. You must negotiate this service with your service provider—it is not a service provided directly through Cisco ER.
NENA	National Emergency Number Association. The organization that recommends data and file formats for ALI definitions and other emergency call requirements in the United States. Cisco ER uses the NENA formats for ALI data export files. Your service provider might have additional restrictions on data format, so ensure that your ALI entries abide by your service provider's rules.
PSAP	Public safety answering point. This is the organization that receives emergency calls, for example, the 911 operator. The PSAP is staffed by people trained in handling emergency calls. The PSAP talks to the emergency caller and notifies the appropriate public service organizations (such as police, fire, or ambulance) of the emergency and its location.

Understanding Cisco Emergency Responder

These topics provide an overview of Cisco Emergency Responder and how you can use it in your network.

Overview of Cisco Emergency Responder Features

These are the major features of Cisco Emergency Responder (Cisco ER):

Compatibility with any emergency number, for example, 911 in North America, 999 in the United Kingdom, 112 in much of Europe, and so forth.
Ability to automatically track movement of many types of phones and to update the ERL of the moved phones without requiring manual intervention. This ensures that emergency calls are routed to the local PSAP even if a phone moves between cities, states, or even countries, and that the correct ALI is presented to the PSAP operator.
Extensive import/export capabilities to help simplify data entry and update.
Four levels of user authority, so that you can assign configuration responsibilities to the required people without exposing all parts of the configuration.
Server redundancy, so that the loss of one server does not disable your emergency call system.
Clustering capability, so that servers can hand calls off to other locations if another location needs to route a call to the PSAP. This allows phone movement between office buildings served by separate phone systems.
Emergency call logging, so that you can track the locations and frequency of emergency calls made on your network.
Onsite security alerting, so that onsite personnel are notified when someone makes an emergency call. Personnel are called with information about the extension of the emergency caller, and they are sent a web-based alert with detailed information about the caller's location. If you configure an email address, they are also sent an email. If the email address is for an email-based pager, they are paged.
Emergency response location (ERL) management:

Ability to create ERLs of any size, from one individual office to as large as you want. This lets you define ERLs that fit your needs and that meet the requirements of your local ordinances.
Ability to export automatic location information (ALI) in a variety of formats, so that you can transmit the ALI to your service provider in the format they require.
Ability to manually assign ERLs to analog phones and other types of phones that Cisco ER cannot automatically track.

Network Hardware and Software Requirements

These tables list the hardware and software that Cisco Emergency Responder (Cisco ER) supports. The type of support can differ between types of hardware, so read the table carefully to determine how Cisco ER will work with the devices you use. See the Release Notes for Cisco Emergency Responder 1.1(4) for the most up-to-date information.

Table 1-2, Part 1—Other software that you must install to use Emergency Responder.
Table 1-2, Part 2—The different types of phones that support Cisco ER. However, the type of support Cisco ER supplies differs depending on the type of phone and the type of switch port to which the phone is attached.
Table 1-2, Part 3—The switches supported for automatic tracking. You can use other switches, but you might have to manually define phones attached to those switches.

Table 1-2, Part 1 Required Software

Item

Minimum Software Version

Description

Cisco CallManager

3.1(4b)

Cisco ER 1.1(4) also supports:

Cisco CallManager 3.1(4b)
Cisco CallManager 3.2(2c); Cisco CallManager 3.2(2c) spE; Cisco CallManager 3.2(2c) spF; Cisco CallManager 3.2(2c) spG
Cisco CallManager 3.3(2) spA

The software that runs the telephony network. You must also install an LDAP directory that Cisco CallManager supports. The directory is used by Cisco ER to store configuration information.

Web browser

Netscape Navigator 4.5 up to, but not including, 6.x
Microsoft Internet Explorer 5.0 and higher

Navigator is supported on Solaris, Windows NT, and Windows 95.

Internet Explorer is supported on Windows 2000, Windows NT, and Windows 95.

Email server

Any SMTP email server

Optional. Used to send email notifications to onsite alert (security) personnel. If you use an SMTP email-based paging server, personnel are paged instead of emailed.

Table 1-2, Part 2 Supported Phones

Phones

Description

Phones automatically tracked using CDP

Cisco IP Phone models 7960, 7940, 7910
Cisco IP Phone 7905G
All other skinny phones with CDP support, with the exception of ATA phones

Note Although ATA phones support CDP and SCCP, Cisco ER cannot automatically track them. You can add ATA phones manually and assign them to an ERL. Cisco ER will route calls from ATA phones based on the assigned ERL.

These phones do not require special Cisco ER configuration. Ensure that you enable CDP (Cisco Discovery Protocol) on the switches.

Note Cisco ER 1.1(4) displays the phone type for the Cisco IP Phone 7905G as "OTHER."

Phones automatically tracked using CAM tables

Cisco IP SoftPhone 1.2 or later
Cisco IP Phone models 12 SP+, VIP 30
All Skinny phones without CDP support

To automatically track these phones, you must enable CAM tracking when you add the switches to the Cisco ER configuration. Phones that do not use CDP are tracked using the CAM table on all supported switch platforms for Native and AUX Vlans.

See the "Identifying the LAN Switches" section for more information.

Phones that you can manually define

Analog phones
Generic H.323 or SIP endpoints
Any phone otherwise supported for automatic tracking that is connected to an unsupported switch port

These phones are only supported if their calls are routed by Cisco CallManager.

See the "Manually Defining a Phone" section for information on defining these phones in the Cisco ER configuration.

Table 1-2, Part 3 Supported Voice-Ready LAN Switches

Switch¹	Notes
Catalyst 6513	Catalyst Operating System 6.1(2) or higher and IOS 12.1(12) or higher
Catalyst 6500 series	Catalyst OS, Hybrid, and Native IOS all support the following: CDP Phone (79XX) Non-CDP Phone (VIP30, Cisco IP SoftPhone, 12sp+)
Catalyst 6000 series	Catalyst OS 5.5 or higher If using an MSFC2 module, Cisco IOS 12.1(3a)XI.
Catalyst 5000 series	Catalyst OS 6.x
Catalyst 4500 series	Catalyst OS 7.2 or higher and IOS 12.1(13)EW(0.22) or higher
Catalyst 4000 series	Catalyst OS 5.5 or higher
Catalyst 3500 XL series	Cisco IOS 12.0(5)XU or higher If you are using 3500 clusters, you must assign an IP address to each 3500 switch.
Catalyst 3550 series	12.1.6.EA1a and higher
Catalyst 2950	12.1.9.EA1 and higher

1 Cisco ER supports only Ethernet ports.

Table 1-3 lists configurations that Cisco ER does not support.

Table 1-3 Non-Supported Configurations

Non-Supported Configurations	Notes
Hub topologies
DSL, VPN, IDSN and other remote or dial-in technologies	Cisco ER cannot support telecommuters who have phones linked into your network over these types of lines
Survivable remote site telephony (SRST)	If you deploy Cisco ER over a WAN link, the link must be active for Cisco ER to work correctly.

How Cisco Emergency Responder Fits Into Your Network

Figure 1-1 shows how Cisco Emergency Responder (Cisco ER) fits into your network.

Figure 1-1 How Cisco ER Fits Into Your Network

Cisco ER depends on Cisco CallManager for the corporate dial plan, which you must modify to send emergency calls to the Cisco ER group. The Cisco ER group also stores the Cisco ER configuration in the Cisco CallManager's LDAP directory. See "Configuring Cisco CallManager for Cisco Emergency Responder," for complete information about the required Cisco CallManager configuration.

To track phones, Cisco ER queries Cisco CallManager for a list of phones registered with the cluster. Then, Cisco ER queries the switches on the network (the ones you have identified to Cisco ER) to determine the port to which the phones are connected. Cisco ER does this tracking at regular intervals during the day so that it can identify when a phone moves. See the "Configuring Switches for Cisco Emergency Responder" section for more information about setting up switches for Cisco ER. See the "Managing Phones" section for information on how to configure switch ports so that Cisco ER can send emergency calls to the correct PSAP based on port and phone location.

Optionally, you can have an SMTP email server (in your network or with a service provider). You can configure Cisco ER to send email to your onsite alert (security) personnel to notify them of emergency calls. If the server is set up as an email-based paging service, the personnel are paged.

Finally, you need a gateway with a PRI or CAMA link to the service provider's network so that Cisco ER can route emergency calls to the local public safety answering point (PSAP).

In this diagram, one Cisco ER group supports a single Cisco CallManager cluster. You can support more than one Cisco CallManager cluster with a single Cisco ER group. If you have a larger network, you can install multiple Cisco ER groups and create a Cisco ER cluster. See the "Understanding Cisco Emergency Responder Clusters and Groups" section for a discussion of this more complex installation.

See the "What Happens When an Emergency Call Is Made" section for an explanation of the path an emergency call takes when Cisco ER manages it.

What Happens When an Emergency Call Is Made

This topic describes the process Cisco Emergency Responder (Cisco ER) uses to handle emergency calls. Understanding this process can help you set up Cisco ER correctly and troubleshoot problems you might encounter.

Figure 1-2 illustrates the path of an emergency call.

Figure 1-2 How Cisco Emergency Responder Routes Emergency Calls

When someone uses extension 3003 to make an emergency call:

Cisco CallManager routes the call to Cisco ER.
Cisco ER determines the emergency response location (ERL) of the caller. The ERL is based on the caller's switch port, unless you manually assigned an ERL to the extension.
Cisco ER converts the calling party's number to the route pattern configured for the caller's ERL. This route pattern is configured to pass the appropriate emergency location identification number (ELIN) to the public safety answering point (PSAP). The ELIN is a telephone number the PSAP can use to call back the emergency caller.
Cisco ER caches a mapping between the caller's extension and the ELIN, by default, for up to three hours. The mapping might be overwritten by subsequent calls before the entry times-out. You can also configure the time-out to be longer or shorter than three hours (see the "CER Group Settings" section).
Cisco ER routes the call using the route pattern configured for the caller's ERL. This route pattern in turn uses the configured route list to send the emergency call to the appropriate service provider's network. The service provider looks up the ELIN in the automatic location information (ALI) database, and routes the call to the appropriate local PSAP. The PSAP receives the phone call and looks up the ALI in the ALI database.
Concurrently, Cisco ER sends alerts to the Cisco ER user web alert page. In addition, Cisco ER calls the onsite alert (security) personnel assigned to the ERL. If you configure an email address for the personnel, Cisco ER also sends an email. If the address is for an email-based paging service, the personnel get pages instead of emails.
If an emergency call is cut off unexpectedly, the PSAP can call back the emergency caller using the ELIN. The call to the ELIN is routed to Cisco ER, and Cisco ER converts the ELIN to the last cached extension associated with the ELIN. The call is then routed to the extension.

Given this methodology, you should consider these major potential points of failure:

For the emergency call to be routed correctly, the caller's phone must be assigned to the correct ERL. This depends on the accuracy of your ERL configuration, the integrity of your wiring closet, and the completeness of your switch port and manual phone configuration.
Another potential problem in routing the call correctly lies with the ELIN definition. If you assign the ELIN's route pattern to the wrong gateway, the emergency call can be routed to the wrong network. This can send the emergency call to the wrong PSAP.

Work with your service provider to determine how many gateways you need and where to connect them. These requirements are based on the service provider's network topology more than on your network's topology. In the United States, the emergency call network is tandem to the PSTN, so simply connecting to the PSTN does not ensure the correct routing of emergency calls.

Finally, the call might be routed incorrectly in the service provider's network if the information in the ALI database is incorrect. Ensure that you export your ALI data and submit it to the service provider, and resubmit it whenever you change ELIN or location information.
The PSAP might not be able to successfully call back an emergency caller if a lot of emergency calls are made in an ERL. Cisco ER caches the ELIN-to-extension mapping for up to three hours. If you have two ELINs defined for an ERL, and three emergency calls are made in a three-hour window, the first ELIN is used twice: once for the first caller, then reused for the third caller. If the PSAP calls the first ELIN, the PSAP will reach the third caller, not the first caller. The likelihood of this problem arising depends on how many ELINs you define for an ERL and the typical rate of emergency calls in the ERL.

Understanding Cisco Emergency Responder Clusters and Groups

Figure 1-3 shows how Cisco Emergency Responder (Cisco ER) groups can be joined in a single Cisco ER cluster.

Figure 1-3 Understanding the Relationship between Cisco ER Groups and Cisco ER Clusters

In this example, Cisco ER groups 1 and 2 form a single Cisco ER cluster. This enables Cisco to handle phone movement between all four Cisco CallManager clusters: CCM-A, CCM-B, CCM-C, and CCM-D.

A Cisco ER group should consist of two Cisco ER servers: a primary server and a standby server. This redundancy can maintain the emergency call network if something happens to the primary server. The standby server also can handle calls if the primary server is too busy handling other calls or tracking phone movements. If the standby server handles a call, all onsite alert personnel (not only those for the caller's ERL) receive the email notification. When the standby server takes over for the primary server, an additional email notification is sent notifying all onsite alert personnel that this has happened.

You create a cluster when you install the individual Cisco ER servers. During installation, you must select two Cisco CallManager servers whose LDAP directories Cisco ER will use to store the Cisco ER configuration:

One Cisco CallManager server whose database is used for storing the Cisco ER group configuration information. In this example, Cisco ER group 1 uses the database for CCM-A, and Cisco ER group 2 uses the database for CCM-D. When you install the servers in a group, ensure that you select the same database for the group configuration.
One Cisco CallManager server whose database is used for storing Cisco ER cluster configuration information. In this example, the Cisco ER groups use CCM-B. It is by choosing the same Cisco CallManager server for cluster information during installation that you create the cluster.

To complete the creation of the Cisco ER cluster, you must create inter-cluster trunks and route patterns to allow the Cisco ER groups to hand off emergency calls between the groups (see the "Creating Route Patterns for Inter-Cisco Emergency Responder-Group Communications" section) and configure these route patterns in Cisco ER (see the "Configuring Group Telephony Settings For the Cisco Emergency Responder Server" section).

Caution Before you create a Cisco ER cluster, be aware that the dial plans in all Cisco CallManager clusters supported by the Cisco ER cluster must be unique. For example, extension 2002 can only be defined in one Cisco CallManager cluster. If you have overlapping dial plans, you must have separate Cisco ER clusters, which means you cannot support dynamic phone movement between those Cisco CallManager clusters.

Be aware of the following when planning your Cisco ER system:

A single Cisco ER group cannot support clusters with a mix of Cisco CallManager versions. For example, Cisco ER can support all Cisco CallManager 3.2(2c) clusters or all Cisco CallManager 3.3(2) clusters. However, a Cisco ER cluster can contain Cisco ER groups that support different versions of Cisco CallManager. In this way, Cisco ER can support a mix of Cisco CallManager versions in your telephony network.
Each group can run different versions of Cisco ER. However, within a single Cisco ER group, Cisco recommends that both Cisco ER servers run the same version of Cisco ER.

Determining the Required Number of Cisco Emergency Responder Groups

To ensure efficient Cisco Emergency Responder (Cisco ER) performance, you should take these practical per-Cisco ER-group limits into account when planning your Cisco ER deployment. Keep in mind that a single Cisco CallManager cluster can only be supported by one Cisco ER group, although a single Cisco ER group can support more than one Cisco CallManager cluster.

A single Cisco ER group can support:

Up to 400 emergency response locations (ERLs).
Up to 30,000 Ethernet switch ports. This is total ports defined in Cisco ER, not just ports to which phones are attached.
Up to 1000 switches.
Up to 10,000 phones.

You might meet the maximum figures for one limitation without reaching the figures for another. For example, you might define 1000 switches, but have less than 30,000 switch ports.

You can install additional groups to manage larger networks.

In addition to these per group limits, you must also consider the territories covered by the service provider's ALI database providers. If your network extends into more than one ALI database provider's territory, you must also divide your Cisco ER groups to accommodate those territories. From each Cisco ER group, you export the ALI data to send to the ALI database provider: ensure that a single Cisco ER group's ALIs only belong to a single ALI database.

Data Integrity and Reliability Considerations

The correct routing of emergency calls to the local PSAP is based on your ERL configuration. Inside your network, correct identification of the ERL for a phone determines the gateway used to connect to the service provider's network. In the service provider's network, the routing is based on the ELIN, which is also used to look up the ALI for the caller. Thus, your ERL configuration must be reliable so that the correct ELIN is assigned to the emergency call.

These are the things to consider to maintain the reliability of your ERL configuration:

ERLs are assigned to switch ports based on the location of the device attached to the port, not the location of the port itself. Thus, if you change the wire plugged into a port (for example, by switching wires between two or more ports), there is the potential that the device now plugged into the port is actually in a different ERL. If you do not change the ERL assigned to the port, the incorrect ELIN will be used for the port, and the wrong ALI sent to the PSAP.

This type of change will not normally result in an incorrectly routed call, because it is unlikely that a single LAN switch will connect to ERLs serviced by separate PSAPs. However, the ALI sent will be incorrect, with the possibility that your security staff will search the third floor for an emergency when the caller is actually on the fourth floor.

To prevent this problem, ensure that your wiring closets are secure, and train your networking staff to avoid swapping wires between switch ports.

If you have phones that Cisco ER cannot automatically track, ensure that any moves, adds, or changes to these phones also result in an update to the Cisco ER configuration. See the "Manually Defining a Phone" section for information on defining these types of phones.
Install standby servers for each Cisco ER group to ensure that the failure of one server does not affect the ability to make emergency calls. Consider installing the standby server in a physically separate location from the primary server, and on a separate subnet. This separation can protect against some types of disruption, for example, a fire in the building housing the primary server, or the loss of connectivity to the subnet hosting the primary server.
Ensure that the Cisco ER configuration is regularly updated as switches are added, removed, or upgraded (for example, by adding or changing modules). When you change a switch, run the switch-port and phone update process on the switch by viewing the switch in Cisco ER and clicking Locate Switch Ports. See the "Identifying the LAN Switches" section for more information.

Any phones connected to undefined switches are listed as unlocated phones in Emergency Responder. If you changed a defined switch, new or changed ports are assigned to the Default ERL, and should be updated to reflect the correct ERL. See the "Understanding the Network Administrator's Role" section and the "Understanding the ERL Administrator's Role" section for information on the recurring tasks involved in network changes.

As you change your ERL/ALI configuration, you must export the information and send it to your service provider for inclusion in the ALI database. This ensures that emergency calls are routed to the correct PSAP, and that the PSAP is presented with the correct ALI. See the "Exporting ERL and ALI Information for Submission to Your Service Provider" section for more information.
Cisco ER directs emergency calls based on the ERL assigned to the phone from which a call is made. Most of the time, the ERL is determined based on the switch port to which the phone is connected. However, if the switch port is not assigned to an ERL, or if the call comes from a phone attached to the network in an unsupported manner, Cisco ER determines the ERL for the phone in this order:

If the phone number is defined as a manual phone, the call is routed based on the manual entry.

If you are sharing a line between an analog phone and an IP phone, and you define the analog phone manually, calls from the shared phone number might be routed based on the manual definition even if the call is from the IP phone. This will occur if the IP phone cannot be located by any Cisco ER group in the cluster.

If the phone is assigned an ERL on the unlocated phones list, and it has not been located in another Cisco ER group in the Cisco ER cluster, the call is routed based on this ERL.
If the phone is on the unlocated phones list but has been located by another Cisco ER group in the Cisco ER cluster, the call is routed to the other Cisco ER group, which handles the emergency call routing.

If Cisco ER cannot direct an emergency call using the route patterns assigned to an ERL, Cisco ER tries to use the route patterns assigned to the Default ERL. If this also fails, Cisco ER routes the emergency call to the security numbers assigned to the ERL (thus directing the emergency call to the onsite alert personnel assigned to the ERL).

Preparing Your Network For Cisco Emergency Responder

These topics describe the steps you should take to prepare your network before deploying Cisco Emergency Responder.

Obtain CAMA or PRI Trunks to the PSTN

To handle emergency calls, you must obtain PRI or CAMA trunks to connect to your service provider. Your service provider might support only one type of trunk. If you have an option, work with your service provider to decide on the type of connection that works best for you.

Consider these issues:

PRI—If you use a PRI connection for emergency calls, you can share the connection with regular telephone traffic. If you use the trunk for regular traffic, monitor trunk usage to ensure there is sufficient available bandwidth to handle emergency calls. If your capacity is inadequate, an emergency caller might get a busy signal when trying to make the call. Ensure you do capacity planning based on emergency call requirements.

When you configure the PRI trunk, you must configure it so that it sends the actual calling party's number rather than a generic number (such as the main number of the site). Otherwise, the PSAP will not receive the expected ELIN, and the emergency call might not be routed to the right PSAP.

CAMA—CAMA trunks are dedicated to emergency calls, and are available in most areas. You do not need to do any capacity planning for CAMA trunks, because they are never used by regular voice traffic.

Work with your service provider to determine how many trunks are required for your network. For example, some service providers use a guideline of two CAMA trunks for 10,000 phones.

Also, the number of trunks can differ depending on the distribution of your offices with respect to the local PSAPs. For example, if you have offices in New York and Chicago, you would need trunks in both cities, even if your total number of telephones would require fewer trunks if your office was only in New York. Your service provider, who knows the layout of the emergency call network, can direct you on trunk requirements that are based on PSAP accessibility.

Obtain DID Numbers from Your Service Provider

You must obtain direct inward dial (DID) numbers from your service provider for use as emergency location identification numbers (ELIN) for your emergency response locations (ERL).

In general, you must have at least one unique number per ERL. Emergency calls are routed to the local PSAP based on the ELIN of the ERL, so if you do not have unique ELINs, the call cannot be routed properly. The ALI database provider also might not accept ALIs that include duplicate ELINs.

You might want to have more than one ELIN per ERL. If your ERLs include more than one phone, you might have more than one emergency call made from an ERL in a short time (less than three hours). If you assign only one ELIN to the ERL, that ELIN is reused for each emergency call. Thus, if four people make emergency calls in the space of an hour, if the PSAP calls the ELIN, the PSAP will connect to the last caller. This might be a problem if the PSAP was trying to contact one of the earlier callers.

If you define more than one ELIN per ERL, Cisco Emergency Responder (Cisco ER) uses those ELINs in sequence until all are used, then reuses the ELINs in order. Cisco ER maintains the link between the ELIN and the extension of the actually emergency caller for up to three hours.

Because you need to purchase these DIDs from your service provider, you must balance the needs of your budget with the needs of maintaining the capability of the PSAP to reach the correct caller.

Note that the number of DIDs you obtain is not related to the number of emergency calls Cisco ER can handle. Because Cisco ER reuses the ELINs you define, every emergency call gets handled and routed to the correct PSAP. The number of ELINs only influences the success rate of the PSAP calling back the desired emergency caller.

Negotiate ALI Submission Requirements With Your Service Provider

Emergency calls are routed to the appropriate PSAP based on the emergency location identification number (ELIN) of the emergency caller. To route the call, the telephony network must have your automatic location information (ALI) that maps these ELINs to a location. Besides routing the call appropriately, the ALI database also supplies the location information that appears on the PSAP's screens to help them locate the caller.

Cisco ER includes features to create ALIs and to export them in a variety of formats that should be acceptable to your service provider. After you create your ERL/ALI configuration, you must export the ALI data and send it to the ALI database provider.

How you send the data can vary from location to location or service provider to service provider. You must work with your service provider to determine the services you can select for submitting ALI data. At the least, you must know the data format they expect, and the transmission method they require.

Cisco ER does not include any automated capability for submitting ALIs.

Tip Before deploying Cisco ER throughout your enterprise, test the ALI submission process with your service provider, and with your service provider's help, test that the PSAP can successfully call back into your network using the ALI data. Each service provider and ALI database provider can have slightly different rules concerning ALI information. Cisco ER allows you to create ALI data according to the general NENA standards, but your service provider or database provider might have stricter rules.

Upgrade Switches and Phones

The most powerful capability of Cisco Emergency Responder (Cisco ER) is the ability to automatically track the addition or movement of telephones in your network. This dynamic capability helps ensure that emergency calls are routed to the local PSAP, even if a user moves a phone between cities. This can reduce the cost of maintaining your telephone network, simplifying moves, adds, or changes.

However, Cisco ER can only automatically track telephone movement for certain types of phones, and for phones attached to certain types of switch ports. See "Network Hardware and Software Requirements" section for a list of these phones and switches.

To enjoy full automation, update your switches to supported models or software versions, and replace your telephones with supported models.

For phones attached to unsupported switches, or for unsupported phones, you can manually assign the phones to ERLs. Thus, these phones are fully supported for emergency calls. The only thing you lose is the automatic tracking capability. See the "Manually Defining a Phone" section for more information.

Preparing Your Staff for Cisco Emergency Responder

Cisco Emergency Responder (Cisco ER) does not replace your existing emergency procedures. Instead, Cisco ER is a tool you can use to augment those procedures. Before deploying Cisco ER, consider how it fits into your procedures, and the use you want to make of Cisco ER's capabilities.

These are the main things to consider when deciding how to make use of Cisco ER:

When someone makes an emergency call, Cisco ER notifies the assigned onsite alert (security) personnel, your emergency response teams, of the location of the caller. This information is, for the most part, the ERL name. Thus, consider working with your emergency response teams to come up with an ERL naming strategy that will help them respond quickly to emergencies. Incorporating building names, floor numbers, and other readily understood location information in the name are the types of things to consider.
Cisco ER lets you define three types of administrative user, so you can divide responsibilities for overall Cisco ER system administration, network administration, and ERL administration. The skills and knowledge necessary for these tasks might be rare to find in one person. Consider dividing Cisco ER configuration responsibilities according to these skills.
The routing of emergency calls, and the transmission of the correct ALI, is only as good as the reliability of the ALI definitions you submit to your service provider, and in the stability of your network topology. Ensure your ERL administrator understands the importance of keeping the ALI data up-to-date, and that your network administrator understands the importance of maintaining a stable network. See the "Data Integrity and Reliability Considerations" section for more information about maintaining data integrity.

Deploying Cisco Emergency Responder

These topics describe deployment models for various types of networks. You can use these examples as modules, combining them to form a larger, more complex network.

Deploying Cisco Emergency Responder in One Main Site with One PSAP

Figure 1-4 shows how Cisco Emergency Responder (Cisco ER) fits into a simple telephony network where you have a single Cisco CallManager cluster.

To support this type of network, install two Cisco ER servers and configure them as a group. During installation, select the same Cisco CallManager server for use as the group and cluster databases.

Because there is only one local PSAP, you only need one gateway to the service provider's network, although capacity planning for your telephony network might require more than one gateway. Configure all route patterns to use this gateway.

See these examples to extend this example to more complex networks:

Figure 1-4 Deploying Cisco ER in One Main Site with One PSAP

Deploying Cisco Emergency Responder in One Main Site with Two or More PSAPs

Figure 1-5 illustrates the Cisco Emergency Responder (Cisco ER) configuration if you have one main site that is served by two or more PSAPs. This example assumes you have one Cisco CallManager cluster. If you have more than one, the setup is logically the same as the one discussed in the "Deploying Cisco Emergency Responder In Two Main Sites" section.

Figure 1-5 Deploying Cisco ER in One Main Site with Two or More PSAPs

To support this type of network, install two Cisco ER servers and configure them as a group. During installation, select the same Cisco CallManager server for use as the group and cluster databases.

Because there are two PSAPs serving the location, you probably need more than one gateway connecting to different parts of the service provider's network. However, this depends on the layout of the service provider's network: you might only need one gateway if the PSAPs are served by a selective router that can intelligently route emergency calls to more than one PSAP. Consult with your service provider to determine the requirements for your buildings. In this example, we assume you will need two gateways. Of course, capacity planning for your telephony network might require more than one gateway for each link.

After setting up the gateways to correctly connect to the service provider's network, configure all route patterns used in Building A ERLs to use gateway A, and all route patterns used in Building B ERLs to use gateway B. As phones move between buildings, Cisco ER dynamically updates their ERLs so that emergency calls get routed out of the desired gateway.

See these examples to extend this example to other networks:

Deploying Cisco Emergency Responder In One Main Site with Satellite Offices

Figure 1-6 illustrates the Cisco Emergency Responder (Cisco ER) configuration if you have one main site that serves one or more satellite offices, that is, where the phones in the satellite office are run from the Cisco CallManager cluster on the main site. If the satellite office has its own Cisco CallManager cluster, see the "Deploying Cisco Emergency Responder In Two Main Sites" section.

Figure 1-6 Deploying Cisco ER in One Main Site with Satellite Offices

Caution In this configuration, if the WAN link between the offices goes down, the people in the satellite office cannot make emergency calls.

To support this type of network, install two Cisco ER servers and configure them as a group. During installation, select the same Cisco CallManager server for use as the group and cluster databases. Install both servers in the main office.

Most likely, there are separate PSAPs serving the main (Columbus) and satellite (Chillicothe) offices. Thus, you probably need more than one gateway connecting to different parts of the service provider's network (you might even have different service providers). However, this depends on the layout of the service provider's network: you might only need one gateway if the PSAPs are served by a shared switch. Consult with your service provider to determine the requirements for your buildings. In this example, we assume you will need two gateways. Of course, capacity planning for your telephony network might require more than one gateway for each link.

After setting up the gateways to correctly connect to the service provider's network, configure all route patterns used in Columbus's ERLs to use gateway COL, and all route patterns used in Chillicothe's ERLs to use gateway CHIL. As phones move between sites, Cisco ER dynamically updates their ERLs so that emergency calls get routed out of the desired gateway.

You might also need to tune SNMP performance to account for the WAN link. Cisco ER must do SNMP queries of the remote site's switches to track phone movements there, and you might run into SNMP time-out problems if you do not allow enough time or retries to make a successful SNMP query. See the "Configuring the SNMP Connection" section for more information.

See these examples to extend this example to other networks:

Tip If the satellite office is small (fewer than 50 phones) and you are using survivable remote site telephony (SRST), it is probably easier to support emergency calls directly by configuring the gateway in the remote office to send 911 calls to an FXO port that has a CAMA trunk to the local PSAP rather than to Cisco ER in the main office.

Deploying Cisco Emergency Responder In Two Main Sites

Figure 1-7 illustrates the Cisco Emergency Responder (Cisco ER) configuration if you have two (or more) main sites, each served by a separate PSAP. You can adapt this example to a more complex setup by combining this discussion with these examples:

If some of your main sites have satellite offices, see the "Deploying Cisco Emergency Responder In One Main Site with Satellite Offices" section for information on deploying Cisco ER in those offices.
If a main site is served by more than one PSAP, see the "Deploying Cisco Emergency Responder in One Main Site with Two or More PSAPs" section for information on deploying Cisco ER in that site.

Figure 1-7 Deploying Cisco ER in Two Main Sites

To support this type of network:

Install two Cisco ER servers in Chicago and configure them as a group. During installation, select the CCM-CHI Cisco CallManager server for use as the group database. Select either CCM-CHI or CCM-NYC as the Cisco ER cluster database.
Install two Cisco ER servers in New York and configure them as a group. During installation, select the CCM-NYC Cisco CallManager server for use as the group database. Select the same Cisco CallManager cluster you selected when installing the Chicago servers for the Cisco ER cluster database.

Most likely, there are separate PSAPs serving your main offices. In this example, Chicago and New York use different PSAPs. You need at least one gateway in Chicago, and one in New York, to connect to different parts of the service provider's network (you might even have different service providers). Consult with your service provider to determine the requirements for your buildings. Of course, capacity planning for your telephony network might require more than one gateway in each site.

After setting up the gateways to correctly connect to the service provider's network, configure all route patterns used in Chicago's ERLs to use gateway CHI, and all route patterns used in New York's ERLs to use gateway NYC.

To enable phone movement between Chicago and New York, you must also configure an inter-cluster trunk to link the Cisco CallManager clusters, and create an inter-Cisco ER group route pattern so that Cisco ER can transfer calls between Cisco CallManager clusters served by separate Cisco ER groups. The "Creating Route Patterns for Inter-Cisco Emergency Responder-Group Communications" section goes into more details about how Cisco ER handles phone movement in this situation.

As phones move between sites, Cisco ER dynamically updates their ERLs so that emergency calls get routed out of the desired gateway. However, if the WAN link becomes unavailable, Cisco ER can not track phone movement between the sites.

See these examples to extend this example to other networks:

Sending Emergency Calls to Company Security

Cisco Emergency Responder (Cisco ER) is designed to route emergency calls to the local public safety answering point (PSAP), and to simplify IP phone mobility with respect to emergency call support. However, if your local ordinances do not require that emergency calls be sent to the local PSAP, you can configure Cisco ER so that emergency calls are sent to onsite security. This topic describes how to modify the Cisco ER configuration to accomplish this.

When you configure ERLs, use ELINs that are not defined in Cisco CallManager. Because the numbers are invalid, Cisco ER routes the call to onsite alert personnel associated with the caller's ERL.

For configuring ERLs, see the "Creating ERLs" section.
Do not create the route patterns and translation patterns as described in the "Setting Up the ELIN Numbers to Route Emergency Calls and Enable PSAP Callbacks" section.

Do not create the CTI ports, and configure Cisco ER's Cisco CallManager settings to use zero (0) telephony ports. This prevents Cisco ER from calling onsite alert personnel associated with an ERL to notify them of the emergency call. This telephone alert is unnecessary because the onsite alert personnel are receiving the actual emergency call.

Do not create the CTI ports as described in the "Creating the Required CTI Ports" section.
Specify 0 for Number of Telephony Ports when configuring the Cisco ER Cisco CallManager settings. See the "Identifying the Cisco CallManager Clusters" section.

When you configure Cisco ER in this manner, emergency calls are directed to the onsite alert personnel defined for the caller's ERL. The onsite alert personnel see the caller's extension as the caller ID, and the call history log shows the onsite alert person's extension instead of the route pattern/ELIN. If there is more than one onsite alert person defined for an ERL, Cisco ER tries the contacts one by one until the call is answered. If no one answers the call, the call is transferred to the call forwarding number defined for the emergency call number.

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